We call this choke a “classic” because amateurs have been using it for more than 50 years on their coax antenna feed lines to stop RFI issues. It's simple to use, inexpensive to deploy, and can be used by beginners as well as experienced hams alike. Learn the basics today and find out how to stop RFi and quiet your ham shack with these simple devices. Helps keep you coax from radiating into other electronics in the house too! Become the hero that prevents RFI, not the villain that creates it with the information manual you get here!